docs: def set_decimal(self, pos, decimal):
          """Turn decimal point on or off at provided position.  Position should be
          a value 0 to 3 with 0 being the left most digit on the display.  Decimal
          should be True to turn on the decimal point and False to turn it off.
          """
          if pos < 0 or pos > 3:
              # Ignore out of bounds digits.
              return
          # Set bit 14 (decimal point) based on provided value.
          if decimal:
              self.buffer[pos*2+1] |= (1 << 6)
          else:
              self.buffer[pos*2+1] &= ~(1 << 6)